spaCy/spacy/strings.pyx

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# cython: infer_types=True
from __future__ import unicode_literals, absolute_import
cimport cython
from libc.string cimport memcpy
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from libc.stdint cimport uint64_t, uint32_t
from murmurhash.mrmr cimport hash64, hash32
from preshed.maps cimport map_iter, key_t
from .typedefs cimport hash_t
from libc.stdint cimport uint32_t
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import ujson
cpdef hash_t hash_string(unicode string) except 0:
chars = string.encode('utf8')
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return hash_utf8(chars, len(chars))
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cdef hash_t hash_utf8(char* utf8_string, int length) nogil:
return hash64(utf8_string, length, 1)
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cdef uint32_t hash32_utf8(char* utf8_string, int length) nogil:
return hash32(utf8_string, length, 1)
cdef unicode _decode(const Utf8Str* string):
cdef int i, length
if string.s[0] < sizeof(string.s) and string.s[0] != 0:
return string.s[1:string.s[0]+1].decode('utf8')
elif string.p[0] < 255:
return string.p[1:string.p[0]+1].decode('utf8')
else:
i = 0
length = 0
while string.p[i] == 255:
i += 1
length += 255
length += string.p[i]
i += 1
return string.p[i:length + i].decode('utf8')
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cdef Utf8Str _allocate(Pool mem, const unsigned char* chars, uint32_t length) except *:
cdef int n_length_bytes
cdef int i
cdef Utf8Str string
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cdef uint32_t ulength = length
if length < sizeof(string.s):
string.s[0] = <unsigned char>length
memcpy(&string.s[1], chars, length)
return string
elif length < 255:
string.p = <unsigned char*>mem.alloc(length + 1, sizeof(unsigned char))
string.p[0] = length
memcpy(&string.p[1], chars, length)
assert string.s[0] >= sizeof(string.s) or string.s[0] == 0, string.s[0]
return string
else:
i = 0
n_length_bytes = (length // 255) + 1
string.p = <unsigned char*>mem.alloc(length + n_length_bytes, sizeof(unsigned char))
for i in range(n_length_bytes-1):
string.p[i] = 255
string.p[n_length_bytes-1] = length % 255
memcpy(&string.p[n_length_bytes], chars, length)
assert string.s[0] >= sizeof(string.s) or string.s[0] == 0, string.s[0]
return string
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cdef class StringStore:
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'''Map strings to and from integer IDs.'''
def __init__(self, strings=None, freeze=False):
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'''Create the StringStore.
Arguments:
strings: A sequence of unicode strings to add to the store.
'''
self.mem = Pool()
self._map = PreshMap()
self._oov = PreshMap()
self._resize_at = 10000
self.c = <Utf8Str*>self.mem.alloc(self._resize_at, sizeof(Utf8Str))
self.size = 1
self.is_frozen = freeze
if strings is not None:
for string in strings:
_ = self[string]
property size:
def __get__(self):
return self.size -1
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def __reduce__(self):
# TODO: OOV words, for the is_frozen stuff?
if self.is_frozen:
raise NotImplementedError(
"Currently missing support for pickling StringStore when "
"is_frozen=True")
return (StringStore, (list(self),))
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def __len__(self):
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"""The number of strings in the store.
Returns:
int The number of strings in the store.
"""
return self.size-1
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def __getitem__(self, object string_or_id):
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"""Retrieve a string from a given integer ID, or vice versa.
Arguments:
string_or_id (bytes or unicode or int):
The value to encode.
Returns:
unicode or int: The value to retrieved.
"""
if isinstance(string_or_id, basestring) and len(string_or_id) == 0:
return 0
elif string_or_id == 0:
return u''
cdef bytes byte_string
cdef const Utf8Str* utf8str
cdef uint64_t int_id
cdef uint32_t oov_id
if isinstance(string_or_id, (int, long)):
int_id = string_or_id
oov_id = string_or_id
if int_id < <uint64_t>self.size:
return _decode(&self.c[int_id])
else:
utf8str = <Utf8Str*>self._oov.get(oov_id)
if utf8str is not NULL:
return _decode(utf8str)
else:
raise IndexError(string_or_id)
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else:
if isinstance(string_or_id, bytes):
byte_string = <bytes>string_or_id
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elif isinstance(string_or_id, unicode):
byte_string = (<unicode>string_or_id).encode('utf8')
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else:
raise TypeError(type(string_or_id))
utf8str = self._intern_utf8(byte_string, len(byte_string))
if utf8str is NULL:
# TODO: We need to use 32 bit here, for compatibility with the
# vocabulary values. This makes birthday paradox probabilities
# pretty bad.
# We could also get unlucky here, and hash into a value that
# collides with the 'real' strings.
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return hash32_utf8(byte_string, len(byte_string))
else:
return utf8str - self.c
def __contains__(self, unicode string not None):
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"""Check whether a string is in the store.
Arguments:
string (unicode): The string to check.
Returns bool:
Whether the store contains the string.
"""
if len(string) == 0:
return True
cdef hash_t key = hash_string(string)
return self._map.get(key) is not NULL
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def __iter__(self):
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"""Iterate over the strings in the store, in order.
Yields: unicode A string in the store.
"""
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cdef int i
for i in range(self.size):
yield _decode(&self.c[i]) if i > 0 else u''
# TODO: Iterate OOV here?
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def __reduce__(self):
strings = [""]
for i in range(1, self.size):
string = &self.c[i]
py_string = _decode(string)
strings.append(py_string)
return (StringStore, (strings,), None, None, None)
def set_frozen(self, bint is_frozen):
# TODO
self.is_frozen = is_frozen
def flush_oov(self):
self._oov = PreshMap()
cdef const Utf8Str* intern_unicode(self, unicode py_string):
# 0 means missing, but we don't bother offsetting the index.
cdef bytes byte_string = py_string.encode('utf8')
return self._intern_utf8(byte_string, len(byte_string))
@cython.final
cdef const Utf8Str* _intern_utf8(self, char* utf8_string, int length):
# TODO: This function's API/behaviour is an unholy mess...
# 0 means missing, but we don't bother offsetting the index.
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cdef hash_t key = hash_utf8(utf8_string, length)
cdef Utf8Str* value = <Utf8Str*>self._map.get(key)
if value is not NULL:
return value
value = <Utf8Str*>self._oov.get(key)
if value is not NULL:
return value
if self.is_frozen:
# OOV store uses 32 bit hashes. Pretty ugly :(
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key32 = hash32_utf8(utf8_string, length)
# Important: Make the OOV store own the memory. That way it's trivial
# to flush them all.
value = <Utf8Str*>self._oov.mem.alloc(1, sizeof(Utf8Str))
value[0] = _allocate(self._oov.mem, <unsigned char*>utf8_string, length)
self._oov.set(key32, value)
return NULL
if self.size == self._resize_at:
self._realloc()
self.c[self.size] = _allocate(self.mem, <unsigned char*>utf8_string, length)
self._map.set(key, <void*>&self.c[self.size])
self.size += 1
return &self.c[self.size-1]
def dump(self, file_):
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"""Save the strings to a JSON file.
Arguments:
file_ (buffer): The file to save the strings.
Returns:
None
"""
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string_data = ujson.dumps(list(self))
if not isinstance(string_data, unicode):
string_data = string_data.decode('utf8')
# TODO: OOV?
file_.write(string_data)
def load(self, file_):
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"""Load the strings from a JSON file.
Arguments:
file_ (buffer): The file from which to load the strings.
Returns:
None
"""
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strings = ujson.load(file_)
if strings == ['']:
return None
cdef unicode string
for string in strings:
# explicit None/len check instead of simple truth testing
# (bug in Cython <= 0.23.4)
if string is not None and len(string):
self.intern_unicode(string)
def _realloc(self):
# We want to map straight to pointers, but they'll be invalidated if
# we resize our array. So, first we remap to indices, then we resize,
# then we can acquire the new pointers.
cdef Pool tmp_mem = Pool()
keys = <key_t*>tmp_mem.alloc(self.size, sizeof(key_t))
cdef key_t key
cdef void* value
cdef const Utf8Str ptr
cdef int i = 0
cdef size_t offset
while map_iter(self._map.c_map, &i, &key, &value):
# Find array index with pointer arithmetic
offset = ((<Utf8Str*>value) - self.c)
keys[offset] = key
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self._resize_at *= 2
cdef size_t new_size = self._resize_at * sizeof(Utf8Str)
self.c = <Utf8Str*>self.mem.realloc(self.c, new_size)
self._map = PreshMap(self.size)
for i in range(self.size):
if keys[i]:
self._map.set(keys[i], &self.c[i])